KR20040089486A - Reciprocating compressor - Google Patents

Abstract

PURPOSE: A reciprocating compressor is provided to reduce noise and vibration generated in operating the compressor, to decrease the number of machined surfaces, and to remove additional parts. CONSTITUTION: A reciprocating compressor(10) is composed of a motor(18) having a crank shaft(22); a piston(38) connected and driven to the crank shaft; and a uni-body member(26) having a body unit(28) for forming a cylinder(30) receiving the piston for a reciprocating motion and a head unit(34) for forming a discharge passage communicating with the cylinder. The body unit and the head unit are formed as a single member. The uni-body member comprises a suction passage(42), discharge chambers(36a,36b) communicating with the discharge passage; a journal unit for receiving the end of a crank shaft(22); and a discharge valve assembly(50) disposed at the head unit and forcibly fitted into the head unit.

Description

Reciprocating Compressor {RECIPROCATING COMPRESSOR}

The present invention relates to a hermetically sealed motor-driven reciprocating compressor, and more particularly to a reciprocating compressor having an improved configuration.

Generally, a hermetic reciprocating compressor includes a sealed casing comprising an upper and a lower shell, a drive motor arranged inside the compression cylinder and arranged in the sealed casing for driving a piston arranged in the sealed casing. Typically, the electric motor includes a crankshaft, a stator and a rotor with an eccentric piston at one end for driving the piston. Typically, the compression cylinder comprises a cylinder block forming a compression chamber, in which the piston is reciprocally linearly by means of a connecting rod disposed between the eccentric of the crankshaft and the piston. Typically, the head portion is mounted to the cylinder block and includes a valve therein to provide controlled discharge of compressed gas from the compression chamber. Due to the high speed operation of the compressor system, a lot of noise and vibration are generated. Therefore, in the field of reciprocating compressors, it is desirable to reduce many noises and vibrations that occur during compressor operation.

In conventional reciprocating compressors, there are a number of machining surfaces that require not only seals or gaskets, but also fasteners for mounting the head to the cylinder block. Thus, in the field of reciprocating compressors, it is also desirable to provide simple manufacturability and assemblability of the reciprocating compressor in order to reduce the number of machining surfaces and to remove additional parts.

Further areas of applicability of the present invention will become apparent from the following detailed description. Although the detailed description and examples illustrate preferred embodiments of the present invention, it is to be understood that it is by way of illustration only and is not intended to limit the scope of the invention.

The invention can be more clearly understood from the following detailed description and the accompanying drawings.

1 is a partial cross-sectional perspective view of a reciprocating compressor according to the present invention;

2 is a detailed partial cross-sectional exploded perspective view of the piston and discharge valve assembly according to the present invention;

3 is a detailed partial cross-sectional perspective view illustrating an assembly technique for mounting a valve plate assembly according to the present invention;

4A is a partial cross-sectional perspective view showing the vertical arrangement of the compressor according to the invention with the motor housing immersed in oil;

4B is a partial cross-sectional perspective view showing the configuration of the compressor mounted inside the sealing shell with the head of the compressor disposed on the oil sump, with the upper side down;

5 is a detailed cross-sectional view showing the connection of the compressor body and the motor cover to the motor stator in accordance with the present invention;

6 is a cross-sectional view showing the connection between the motor stator and the motor cover and the lower bearing housing in accordance with the present invention;

7 is an exploded perspective view of the snap fit discharge tube fitting;

8A is a cross sectional view of a thrust bearing used in the compressor of FIG. 4A;

FIG. 8B is a cross-sectional view of an oil plug provided on top of the crankshaft used in the compressor of FIG. 4A; FIG.

9A is a cross sectional view of a thrust bearing used in the compressor of FIG. 4B;

FIG. 9B is a cross sectional view of an oil plug provided on top of a crankshaft used in the compressor of FIG. 4B; FIG.

10 is a detailed cross-sectional view illustrating the connection of a compressor body and a motor cover to a motor stator according to an alternative embodiment of the present invention;

11 is a detailed cross-sectional view illustrating the connection of a compressor body and a motor cover to a motor stator according to another alternative embodiment of the present invention.

(Example)

The following description of the preferred embodiments is merely exemplary and does not limit the scope thereof in use or use.

Referring to Fig. 1, a hermetic sealed reciprocating compressor 10 according to the present invention will be described. The reciprocating compressor 10 comprises a sealing casing 12 comprising a lower shell 14 and an upper shell 16 which are hermetically connected to each other. The sealing casing 12 is provided with a suction inlet passage 17. As is well known in the art, a motor 18 is disposed inside the casing 12, which includes a rotor (not shown), a stator 20, and a crankshaft 22 connected to the rotor. The crankshaft 22 includes an eccentric 24.

The motor 18 includes a motor cover 25. The motor 18 is equipped with a uni-body member 26. The uni-body member 26 includes a body portion 28 forming a cylinder 30 and a bell shaped housing portion 32. A head portion 34 is formed integrally with the body 28, and the head portion includes a first discharge cavity 36a in communication with the cylinder 30, and the second discharge cavity 36b includes a restriction portion 36c. And communicates with the first discharge cavity 36a. The size of the first and second discharge chambers 36a, 36b is preferably a size that optimizes the discharge pulse or efficiency. In addition, the restriction 36c may be sized to further optimize the discharge pulse or an insert may be provided. The discharge tube 100 is connected to the outlet port 102 of the second discharge chamber 36b. Discharge tube 100 preferably snap-fits engagement with outlet port 102. In particular, as shown in FIG. 7, the discharge tube 100 may be provided with a tube fitting 104 having a retainer ring 106 that extends radially, the ring being pressurized to exit port 102. As it passes through it expands outwards to prevent tube fitting 104 from being removed or pulled out. The compliant seal member 105 forms a generally gas-tight seal between the outlet port 102 and the tube fitting 104. Optionally, a muffler 108 may be provided in the discharge tube passage 100. The discharge tube 100 is connected to the discharge port 110 provided in the sealing casing 12.

The piston 38 is arranged inside the cylinder 30 and is connected to a connecting rod 40 connected to the eccentric 24 of the crankshaft 22. A suction passage 42 is provided in the uni-body member 26 and communicates with the hollow part 44 and the cylinder 30 formed by the bell part 32 of the body 28. As shown in FIGS. 2 and 3, the piston 38 is generally cylindrical in shape and includes a concave groove 46 in communication with the inlet passage 48, a suction passage 42, a groove 46, and Allows passage of gas from the top of the piston 38 to the cylinder through the inlet passage 48 and through the passage 47, and during the suction phase of the compressor operation, the passage 47 (fastened to the top of the piston) It is covered by the suction reed valve 49.

The discharge valve assembly 50 is provided at the open end of the cylinder 30. The discharge valve assembly 50 includes a valve plate 52, a discharge valve member 54, and a valve retainer 56. The valve plate 52 is generally disc shaped and has a pair of outlet ports 58 disposed thereon. The valve plate 52 also includes a plurality of holes 60 for receiving fasteners for mounting the discharge valve 54 and the retainer 56 to the valve plate 52. As shown in FIG. 2, the discharge valve 54 is a reed-type valve made of a flexible material. The discharge valve 54 is disposed with respect to the valve retainer 56 having an arcuate surface 62, the mounting hole 60 provided in the valve plate 52, and the hole 66 provided in the discharge plate 54. It also includes a mounting hole 64 (only one is shown in FIG. 1) for receiving the fasteners extending through. The discharge valve 54 is arranged radially inward from the discharge port 58 provided in the valve plate 52 and covers the discharge port 58 during the suction phase of the compressor operation and discharge port 58 during the compressed state of the compressor operation. Arcuate cutouts 68 that help control the flexibility of the discharge valve 54 to bend away. The arcuate surface 62 of the valve retainer 56 has a shape configured to restrict the opening of the reed valve 54 for optimization of stress and efficiency.

The discharge valve assembly 50 is configured such that the valve plate 50 has a diameter that is properly machined and dimensioned to allow an interference fit between the outer diameter of the valve plate 52 and retainer 56 and the inner diameter of the cylinder 30. 52 and the retainer 56 can be assembled to the head 34 of the uni-body member 26. The interference fit in diameter provides sealing and retention of the valve plate 52 and the retainer 56. In assembly, the piston 38 is held in a predetermined position, such as, for example, top dead center, and the discharge valve assembly 50 is cooled to a temperature low enough to heat shrink the diameter of the assembly 50 and freely into the cylinder 30. Fall down. Discharge valve assembly 50 is positioned on piston 38 until it is heated to pressure fit cylinder 30. The pressure fit retains the assembly 50 and provides a seal between the cylinder 30 and the outlet valve assembly 50 diameter. As shown in FIG. 3, one method of positioning the piston 38 inside the cylinder 30 upon assembly of the discharge valve assembly 50 is by connecting the connecting rod 40 (by applying a force F). This imposes a reverse load on the bearing between the crankshafts 22, which depends on the bearing clearance to position the piston 38 just above the normal top dead center position. The gas force (when the compressor is in operation) pushes the piston down, reverses the load on the bearing, and produces a cooling piston clearance for the valve plate that is approximately equal to the sum of the bearing clearances in the actuating gear assembly.

Note that an interference fit in the assembly can be obtained by heating the cylinder to allow the cylinder bore to expand before inserting the outlet valve assembly into the cylinder, as opposed to cooling the outlet valve assembly and keeping the cylinder at room temperature. Should be. And it is also possible to combine the two (heating the cylinder and cooling the discharge valve assembly). And the sealing and holding between the valve plate 52 and the cylinder 30 can be strengthened by using a sealant such as, for example, LOCTITE.

An alternative embodiment is to install the valve plate in a counterbore of a different diameter than the cylinder. However, this alternative requires additional machining to form the counterbore.

As shown in FIG. 2, the top of the piston 38 has a contoured post designed to partially fill the outlet port 58 of the valve plate 52 when the piston 38 approaches top dead center. 70). The contoured post 70 further reduces the amount of clearance between the piston 38 and the valve plate 52 at top dead center, further increasing the efficiency of the compressor.

The uni-body member 26 includes a bearing portion 72 for receiving an end of the crankshaft 22. The uni-body member 26 further includes an opening 74 in the bell-shaped portion 32 spaced apart from the bearing portion 72 and containing the crankshaft 22. A crankcase isolation seal 76 is disposed between the opening 74 and the crankshaft 22 to provide a large suction volume inside the hollow 44 to reduce suction pulses. The suction gas flowing through the suction inlet passage 17 passes over the top of the upper edge of the motor cover 25 into the motor cover 25 and between the inside of the motor cover 25 and the outer surface of the stator 20. Is delivered. The suction gas then passes upward between the rotor and the stator 20 and into the space between the stator 20 and the hollow 44 of the bell-shaped portion 32 of the body 28. The free volume between the motor 18 and the bell 32 is useful for acting as a suction muffler. Additionally, the seal prevents oil from the upper main and connecting rod bearings flowing down past the crankshaft and incorporated into the intake gas. In addition, the intake gas flow passage also prevents oil from being incorporated into the intake gas. By constructing the uni-body member 26 as a single casting forming a body 28 comprising a cylinder 30 and an outlet cavity 36 inside the head 34, a significant reduction in the number of machining surfaces And removal of the fastener for attaching the seal or gasket and head to the body.

4A and 4B, the sealing casing 12 is sized to support the motor 18 and the uni-body member 26 for two different types of applications. Oil temperature control is important for most hermetic compressors. If the oil is too hot, the lubricity will be poor and oil failure may occur. If the oil is too cold, the refrigerant dilution can have a significant impact on the lubricity of the oil or negatively affect the reliability of the compressor. The oil sump temperature depends heavily on how the compressor is applied. In applications with high overheat and high pressure ratios, dissipating the least amount of heat in the oil helps to keep it in a safe temperature zone. This can be accomplished by keeping the head of the compressor out of oil. Applications with low overheating and low pressure ratios can be advantageous from heat release to oil. This heat release to oil can be enhanced by immersing the head and actuating gear in oil.

Thus, the present invention provides a sealed casing with a motor disposed on the compressor sump as shown in FIG. 4A, or with a uni-body member 26 disposed on the compressor sump, as shown in FIG. 4B. Provided that 12 is configured to receive a motor 18 and a uni-body member 26. A change necessary to do this is to use a crankshaft thrust bearing with an oil sump at the end of the crankshaft immersed inside the oil sump. Referring to FIG. 8A, a cross section of the crankshaft thrust bearing 120 is shown for the compressor shown in FIG. 4A. In particular, the thrust bearing 120 includes a thrust washer 122 disposed between the end of the crankshaft 22 and the lower bearing housing 92. A bearing 123 is provided between the crankshaft 22 and the lower bearing housing 92.

FIG. 8B shows an oil plug 124 provided on top of the crankshaft 22 of the embodiment of FIG. 4A. The plug 24 has a blowout passage 126 to allow the ejection of gas while preventing oil from ejecting out of the top of the crankshaft 22 to control the oil circulation rate.

FIG. 9A shows a cross section of the crankshaft thrust bearing 130 for the compressor shown in FIG. 4B. In particular, the thrust bearing 130 includes a thrust washer 132 disposed between the bottom of the crankshaft and the retainer ring 134 attached to the body 28. FIG. 9B shows an oil plug 136 provided on top of the crankshaft 22 of the embodiment of FIG. 4B. The plug 136 has a blowout passage 138 to allow the ejection of gas while preventing oil from ejecting out of the top of the crankshaft 22 to control the oil circulation rate. In current designs, the same members of the compressor design, including housings, motors, and uni-body members, can be used in compressors used for high or low overheat and pressure ratios.

Referring to FIG. 1, the outer diameter of the stator 20 is pressure-fitted to the counterbore inner diameter of the bell-shaped portion 32 of the uni-body member 26. The stator 20 is a structural member that supports bearing loads and suspension system loads. As shown in FIG. 5, an alternative embodiment relies on the epoxy gun gap in the bell bore's counter bore to allow positioning of the stator 20. The stator can be held in place with a tack weld during epoxy curing. As shown in FIG. 10, another alternative embodiment includes a bolt extending through the housing 25, the stator 20 and screwed with the bell 32, the stator 20 to position the stator ( 150 is clamped against the surface of the bell 32. As an alternative, as shown in FIG. 11, the bell 32 can be connected to the stator 20 by welding 151.

The motor 18 includes a motor cover 25, which can be pressure-fitted on the stator 20, as shown in FIG. 1. The motor cover may be provided with an indent 25A that engages with the stator and forms an air gap between the motor cover 25 and the stator 20 to allow the flow of intake gas therebetween. An alternative embodiment is to plug-weld the motor housing cover 25 to the stator 20. As shown in FIG. 5, plug welding may be used with a pressure fit or to position the housing into the epoxy fill gap 86. An air gap shim can be used during curing and then removed to form an air gap for the intake gas. Alternatively, motor cover 25 may be secured to the stator by bolts 150, as shown in FIG. 10, or connected by welding 152, as shown in FIG. 11.

Another alternative embodiment is to use a two part motor cover housing that includes a motor cover 90 and a lower bearing housing 92, as shown in FIG. 6. As described above, the motor cover 90 is pressure-fitted, bonded, bolted, and / or welded to the stator 20. The lower bearing housing 92 is laterally moved to position the lower bearing relative to the lower end of the crankshaft 22 and the lower bearing housing 92 is then plug welded to the motor cover housing 90. The separate connection of the lower bearing housing 92 allows the rotor and crankshaft 22 to be properly positioned relative to the stator 20 to provide a suitable air gap between the rotor and the stator 20 for efficient operation.

During operation, as is well known in the art, oil is guided through thrust bearings and through crankshaft 22 with internal lubrication passages. The crankshaft 22 is provided with radial passages 142, 144 to provide lubrication to the inner passage of the connecting rod 40 and the upper crankshaft bearing. The cylinder 30 is splash lubricated by lubrication from the connecting rod 40.

The description of the present invention is merely exemplary, and thus, many changes without departing from the technical idea of the present invention are included in the technical idea of the present invention. Such changes are not to be regarded as a departure from the technical spirit of the present invention.

According to the present invention, there is provided an reciprocating compressor of an improved configuration, which reduces many noises and vibrations generated during operation of the compressor, reduces the number of machining surfaces and removes additional parts.

Claims (34)

A motor including a crankshaft; A piston connected to and driven by the crankshaft; And A uni-body member comprising a body portion forming a cylinder for receiving the piston for reciprocating motion and a head portion forming a discharge passage communicating with the cylinder; And the body portion and the head portion are formed as a single member. 2. The compressor as claimed in claim 1, wherein the uni-body member includes a suction passage. 2. The compressor as claimed in claim 1, wherein the uni-body member includes a discharge chamber in communication with the discharge passage. 2. The compressor as claimed in claim 1, wherein the uni-body member includes a journal portion for receiving an end of the crankshaft. 2. The compressor as claimed in claim 1, further comprising a discharge valve assembly disposed in the head portion of the uni-body member. 6. The compressor as claimed in claim 5, wherein the discharge valve assembly is fitted in the head portion. 6. The compressor as set forth in claim 5, wherein said discharge valve assembly includes a valve plate disposed at the top of said cylinder, a valve member disposed relative to said valve plate, and a retainer disposed relative to said valve member. 8. The compressor as claimed in claim 7, wherein said valve member is a flexible reed valve. 2. The compressor as claimed in claim 1, wherein the crankshaft extends through an opening of the uni-body member and comprises an isolation seal disposed between the crankshaft and the opening. 10. The apparatus of claim 9, wherein the body portion of the uni-body member includes a hollow portion for receiving a portion of the motor, wherein the uni-body member defines a suction passage in communication with a space between the hollow portion and the motor. Compressor, characterized in that. 2. The compressor of claim 1, further comprising a compressor shell having a first end and a second end, each connected by an intermediate portion, the compressor shell being the first end or the second end of the motor and the compressor shell. And configured to receive the uni-body member disposed at either of the ends. 2. The compressor as claimed in claim 1, wherein said body portion of said uni-body member comprises a hollow portion for receiving a stator of said motor. 13. The compressor as claimed in claim 12, wherein the body portion of the uni-body member is pressure-fitted to the stator of the motor. 13. The compressor as claimed in claim 12, wherein the body portion of the uni-body member is fixed to the stator of the motor by an adhesive. 13. The compressor as claimed in claim 12, wherein the body portion of the uni-body member is bolted to the stator of the motor. The compressor of claim 1, wherein the motor includes a motor cover connected to the stator of the motor. 17. The compressor of claim 16, wherein the motor cover includes a cover body connected to the stator, and a lower bearing housing supporting the lower motor bearing and mounted to the cover body. 2. The compressor as claimed in claim 1, wherein the piston includes at least one post at the top, and the post is received in a discharge port communicating with the discharge passage. A motor including a crankshaft; A piston connected to and driven by the crankshaft; A cylinder for receiving the piston for reciprocating motion; And a head portion forming a discharge passage communicating with the cylinder. It includes, and And a discharge valve assembly adapted to fit the cylinder. 20. The compressor of claim 19, wherein the discharge valve assembly includes a valve plate disposed on top of the cylinder, a valve member disposed relative to the valve plate, and a retainer disposed on the valve member. 21. The compressor of claim 20, wherein the valve member is a flexible reed valve. 20. The valve assembly of claim 19 wherein the valve assembly comprises a valve plate and the interference fit is: Maintaining a piston at a predetermined position inside the cylinder; Thermally contracting the valve plate and inserting the valve plate at an open end of the cylinder to be positioned on the piston; And Heating the valve plate to expand and pressure fit with the cylinder; Compressor, characterized in that formed by a method comprising a. 20. The compressor of claim 19, wherein the method further comprises securing a valve retainer to the valve plate and providing a discharge valve between the valve plate and the valve retainer. 20. The method of claim 19, further comprising: thermally contracting a valve retainer mounted to the valve plate and inserting the valve retainer together with the valve plate into the cylinder to expand the valve retainer and heat it to pressure fit with the cylinder. Method comprising a. 20. The method of claim 19, wherein maintaining the piston in a predetermined position within the cylinder includes applying a reverse load to a bearing of a connecting rod connected to the piston. 20. The method of claim 19, wherein the piston comprises at least one post at the top, the post being received at an outlet port of the valve plate. 20. The valve assembly of claim 19 wherein the valve assembly comprises a valve plate and the interference fit is: Maintaining a piston at a predetermined position inside the cylinder; Thermally expanding the cylinder and inserting a valve plate at the open end of the cylinder to be positioned on the piston; And Cooling the valve plate to retract and pressure fit with the valve plate; Compressor, characterized in that formed by a method comprising a. The method of claim 1, An opening in the body member through which the crankshaft extends; And And an isolation seal disposed between said crankshaft and said opening. 29. A body according to claim 28, wherein said body portion of said body member comprises a hollow portion for receiving a portion of said motor, said body member defining a suction passage in communication with a space between said hollow portion and said motor. Compressor. The method of claim 1, A stator on the motor; And A motor cover connected to the stator; The motor cover and the stator further comprises a suction gas passage therebetween. 22. The compressor as claimed in claim 16 or 21, wherein the motor cover is press fitted on the stator. 31. The compressor as claimed in claim 16 or 30, wherein the motor cover is fixed to the stator by an adhesive. 31. The compressor of claim 30, wherein the motor cover comprises a cover body connected to the stator of the motor, and a lower bearing housing supporting the lower motor bearing and mounted to the cover body. The method of claim 1 wherein: A motor including a crankshaft; A piston connected to and driven by the crankshaft; A body member forming a cylinder for receiving the piston for reciprocating motion, and a head portion defining a discharge passage communicating with the cylinder; And An outlet valve assembly disposed in the cylinder and including at least one outlet port and at least one post on a top surface of the piston; And a post is received at the discharge port.